Theme Check Plugin

I am developing a wordpress theme for my school. It was working very fine, just one fine day i decided to check it against theme check plugin. it is able to pass all the criteria but when ever i enable debug mode it start displaying a lots of error on the backend, and suggesting settings-api instead of my _post method.

Later on, i downloaded some famous free themes from the internet and to my surprise none of them is able to pass the criterias in debug-mode either on front-end or in backend. But they are working fine.

My question is – is it theme check benchmark for a quality wordpress theme?

Kindly guide me.